In recent years the UK has seen the establishment several so-called "paedophile hunter" groups similar to the one which uploaded footage of an RTÉ producer who was allegedly attempting to engage in sexual activity with a 13-year-old last weekend.
The groups were inspired by the American reality TV show To Catch a Predator, which employed women pretending to be underage girls online as bait to lure out potential child abusers.
When the men came to meet the "child" they were confronted by the show's host Chris Hansen before being arrested by local police. The show was cancelled in 2008 after one of the men it targeted shot himself.
The UK groups use similar tactics. They trawl chat rooms pretending to be children or young teens in the hope of engaging men before asking them to meet in real life, usually in a public location like a coffee shop.
If the target agrees to meet, the group shows up and confronts the man, usually in a highly public fashion. Everything is caught on camera and the footage is uploaded online soon afterwards, as happened in the case of RTÉ producer Kieran Creaven, who was confronted in Leeds by a group calling itself Predator Exposure.
The videos are hugely popular. The one involving Mr Creaven has already been viewed almost 400,000 times across various platforms. Some of the UK groups also operate in Ireland.
Underage girls
Coincidentally, one UK group confronted two men at their homes in Drogheda last Saturday and accused them of trying to meet underage girls. Gardaí are investigating.
Unlike in America, UK police forces are generally opposed to such groups, although they sometimes use the evidence they gather when prosecuting offenders.
For example in 2013 a retired university lecturer was jailed for a year after being caught in an online sting by the self-styled paedophile hunter Stinson Hunter, real name Kieren Parsons. Mr Parsons estimates his operations have secured 17 convictions.
But police complain the footage and chat logs gathered by the groups are often unusable in court as they have not been subjected to the usual rules concerning chains of evidence.
They also maintain the groups’ tactics of confronting the men gives them time to get rid of evidence before the police become involved.
Even if police are unable to prosecute, the consequences for men targeted by vigilante groups are severe. Many have lost their jobs, families and friends after footage surfaced online.
In 2013 a man took his own life days after being confronted by Letzgo Hunting and accused of trying to meet up with a 14-year-old girl.
Sometimes the men say they are innocent of any wrongdoing. The Guardian newspaper interviewed a man who said he pulled out of a meeting when the “girl” he had been chatting to online texted him and said she was 15. He had previously thought she was 18.
Nonetheless he was confronted by the vigilante group on a public street and accused of being a paedophile. Footage later appeared online.
Although police reviewed the footage and said there was no evidence of any offence, the man was forced to move to the other side of the country to escape death threats.